1. Field of the Invention
The present invention generally relates to mounting hardware for securing warning light arrays to motor vehicles and more particularly to a mounting foot assembly for securing a lightbar to the roof of a motor vehicle.
2. Description of the Related Art
Lighting systems for mounting on the exterior of police and other public service vehicles have long been known in the art. Exterior mounting of such lighting systems is generally preferred in order to enhance the visibility thereof, i.e., a warning light mounted above the roof of an emergency vehicle may be more readily seen than a light mounted below the vehicle roof line or within the vehicle. Such exterior mounting also affords the possibility of the emitted light being seen from any direction and minimizes the possibility that the light produced by the lighting system will interfere with the vision of the vehicle operator.
A long-standing problem associated with lightbar assemblies resides in mounting the assembly to the vehicle in such a manner that it may be easily positioned as desired on the vehicle and, most importantly, will not become loose due to vibration or other causes and either change position or become dislodged. There are, of course, many mounting assemblies known in the prior art for attaching devices to the roof of a motor vehicle. U.S. Pat. No. 4,588,118 (hereinafter the '118 patent), assigned to the assignee of the present invention, discloses a mounting foot assembly for securing a lightbar to the exterior of a motor vehicle. Specifically, the mounting foot assembly includes a mounting member foot portion and gutter clamp which support the mounting member in clamped relationship to a rain gutter of the motor vehicle. An upwardly projecting portion of the mounting member has laterally projecting tabs for engagement with inwardly facing longitudinal slots defined by an I-beam extruded aluminum strength member. The mounting foot assembly includes locking cams configured to extend outwardly to engage the bottom of the longitudinal slots. When secured in their engaged position, the locking cams secure respective of the mounting members to the I-beam and urge the corresponding gutter clamp inwardly to secure the mounting foot assembly to the gutters at the opposite sides of the vehicle.
While the lightbar mounting foot assembly disclosed in the '118 patent has been commercially successful and provided a secure engagement between the lightbar and the motor vehicle, further improvements in lightbar mounting are possible. For example, modern motor vehicle design has eliminated the outwardly projecting rain gutter and thus a convenient clamping location. Further, reinforced plastic materials may be used to form a mounting foot having improved efficiency of manufacture and aesthetic appearance. These changes result in the need for a new and effective mounting foot assembly that is compatible with modern vehicle configurations and mounting foot materials.
The lightbar disclosed in the '118 patent, as well as that disclosed in U.S. Pat. No. 5,027,260 (hereinafter the '260 patent), also assigned to the assignee of the present invention, are constructed around a longitudinally extending extruded aluminum strength member. This strength member may be in the form of an I-beam as shown in the '118 patent, a concave channel as shown in the '260 patent, or the like. Extrusion is an efficient method for obtaining a strength member of high rigidity having a complex sectional configuration. Longitudinally extending features are arranged for the mounting of lightheads, internal components such as power supplies to the interior of the extrusion and exterior components such as lenses to the exterior of the extrusion.
Typically, components are engaged with longitudinal features defined by the extrusion and slid along the length of the extrusion into a desired position where they are secured in place by set screws bearing against the extrusion. Brackets or mounting feet for a lightbar have been fixed to the bottom exterior surface of the lightbar strength member in a similar manner. Lightbars are typically assembled according to a customer's specification and shipped to the customer for installation on a motor vehicle. In a fully assembled lightbar, end caps may cover entry openings for all of the longitudinally extending features, including the inwardly facing slots configured to receive the upper portions of mounting brackets or mounting feet. In such a lightbar, the feet must be mounted to the lightbar prior to installation of the end caps or the lightbar must be partially disassembled by the end user to accommodate mounting of the support foot or mounting bracket. Shipping a lightbar with the mounting feet attached increases the cost of shipping and also increases the likelihood of breakage during shipment. End user disassembly and re-assembly of lightbar components to the extrusion complicates lightbar installation. Disassembly also presents the possibility of leakage and premature failure of lightbar components.
There is a need in the art for a mounting foot for a lightbar which is compatible with an extruded lightbar strength member and which does not require disassembly of the lightbar for mounting the foot to the lightbar strength member. Preferably, a mounting foot will have features that lock the foot to the strength member to prevent loosening during use.